钻削机构与煤岩互作用系统耦合动力学研究

摘要

针对因井下煤岩复杂性及钻削煤岩时冲击、钻削机构间扰动、煤岩-钻头-钻杆系统的耦合振动，使钻削式破岩机构运动规律、动力学行为、可靠性难以有效控制、预测问题，考虑钻头与煤岩互作用的实际载荷及钻杆与孔壁煤岩接触碰撞载荷，将钻杆离散成有限个单元，建立钻削机构与煤岩互作用系统耦合非线性动力学模型，研究钻削机构在煤岩硬度 f＝4．65，f＝3．7，f＝2．7及不同转速下纵向、横向、扭转振动及不同条件下钻削机构振动试验。结果表明，随煤岩硬度的减小，钻杆横向振动半径、纵向振动频率及幅值均有所减小；对相同硬度煤岩，钻杆横断面上位移最大半径随深度变化始终呈指数关系；在研究的转速范围内，耦合系统横向振动受转速变化影响不大，且转速变化均仅改变纵向、扭转振动曲线幅值。可为钻削机构设计提供理论依据。%It is difficult to control and predict the motion,the dynamics action and the reliability of a drilling mechanism in the process of drilling coal rock due to the complicacy of coal rock,the contact impact between drill pipe and coal rock and the coupling vibration of coal rock-drill bit-drill pipe system.Considering the interacted load between drill bit and coal rock and the contact load between drill pipe and coal rock wall,and discretizing the drill pipe by a number of finite elements,the coupling nonlinear dynamics model of the drilling system was built.The longitudinal, transverse and torsional coupled vibration was studied under the conditions of different coal rock hardness and different rotating speed of drill bit.The vibration of drilling mechanism was discussed through experiments under different conditions.The results indicate that the transverse vibration radius,the longitudinal vibration frequency and amplitude are all reduced when the coal rock hardness decreases;and for coal rock with the same hardness,the biggest transverse vibration radius is in exponential relation with the drilling depth;the change of rotating speed only changes the amplitude of longitudinal and torsional vibrations and has only a little effect on transverse vibration.The results provide a theoretical basis for the design of drilling mechanism.